Accompanying the reduced size and thickness of electronic devices, surface mount packages are being increasingly used for electronic components provided in these electronic devices. Examples of such packages include packages in which a semiconductor chip is mounted on a board such as a chip-on-board (BOC) package. These packages employ a structure in which the semiconductor chip and board are bonded. Consequently, warpage and other forms of package deformation occurred due to temperature changes attributable to a difference in the coefficient of thermal expansion (CTE) between the semiconductor chip and the board. In addition, as this warpage increases, force that acts to separate the semiconductor chip and board becomes large, thereby causing a decrease in connection reliability between the semiconductor chip and board in these packages.
In addition, electronic devices are being required to become even smaller and thinner. In order to satisfy these demands, efforts are being made to reduce the size and thickness of electronic components, and studies are being conducted to reduce the thickness of the boards that compose the packages of electronic components. In the case of a board that has been reduced in thickness in this manner, there tends to be increased susceptibility to the occurrence of warpage, thereby requiring these boards to more effectively inhibit the occurrence of warpage.
Moreover, in order to make electronic devices multifunctional, it is necessary to increase the number of electronic components installed therein. In order to satisfy this requirement, a type of package known as a Package on Package (PoP) is employed in which a plurality of sub-packages are laminated and mounted on a board followed by integrating into a single package. For example, these PoP are frequently employed in portable terminal devices such as Smartphones or tablet computers. In addition, since these PoP are of a form in which a plurality of sub-packages are laminated, the connection reliability of each sub-package becomes important. In order to enhance this connection reliability, it is necessary to reduce warpage of each package that is used as a sub-package.
On the basis thereof, studies have been conducted on the development of board materials that enable the production of boards that are able to adequately inhibit warpage even in the case of packages using boards of reduced thickness. An example of these board materials is the resin composition described in WO 2012/099134.
WO 2012/099134 describes a resin composition containing a maleimide compound having at least two N-substituted maleimido groups in the structure of a single molecule thereof and a silicone compound having at least one amino group in the structure of a single molecule thereof.
According to WO 2012/099134, it is disclosed to the effect that a multilayer printed wiring board can be produced that has superior glass transition temperature, coefficient of thermal expansion, soldering heat resistance and warpage characteristics, and is useful as a printed wiring board for electronic devices.
However, when using a board obtained using the resin composition described in WO 2012/099134, there are cases in which a package is unable to be obtained that adequately inhibits warpage and other deformation that occurs due to changes in temperature.
In this manner, a bonded body obtained by bonding two or more members made of different materials is subjected to stress in the direction in which warpage occurs caused by a change in temperature that is due to a difference in the coefficient of thermal expansion of each member. Consequently, in the case of a bonded body in which two or members made of different material are bonded, the problem of the occurrence of warpage caused by a change in temperature may occur in the same manner as in the case of the packages described above. In addition, the problem may also occur in which the bonded state of two members may be unable to be maintained. It is therefore necessary to inhibit the occurrence of such problems.
With the foregoing in view, an object of the present invention is to provide a resin composition that allows the obtaining of a compact that adequately inhibits the occurrence of warpage even in the case of bonding to another member. In addition, an object of the present invention is to provide a resin varnish, a prepreg, a metal-clad laminated board and a printed wiring board that use this resin composition.